Problem: when I try to send something (ex ping) from Edimax to PC THRU
WiFi, at the beginning it works. After ARP times out, response is "no
response from PC". /proc/net/arp shows PC IP addr with zeros (unresloved
AFAIK).

If then I issue ex ping from PC -> ARP becomes valid, ping works.

Question: where to look to try to solve this? Does IPTABLES on PC in
some kind blocks ARP? (as it name suggests it shouldn't). On PC I have
full normal "toolkit", but on Edimax my tools are VERY limited.

Problem was with network driver: it seems that the one located in
/kernel/rtl8186 (rtl8186.o file, small: 17K) is buggy. When changed to
driver in /kernel/drivers/net/rtl8186.o (a big one 195K) problem with
ARP is gone. Switching drivers is mage by kernel .config: